CVE-2026-42449 n8n-MCP: IPv4-mapped IPv6 addresses bypass SSRF protection in validateUrlSync(), enabling full SSRF for SDK embedders

n8n-MCP is an MCP server that provides AI assistants access to n8n node documentation, properties, and operations. In versions 2.47.4 through 2.47.13, the SDK embedder path N8NDocumentationMCPServer constructor, getN8nApiClient, and validateInstanceContext, the synchronous URL validator in...

CVE-2026-42449

Summary: CVE-2026-42449 affects n8n-mcp SDK embedder paths where SSRF protection (SSRFProtection.validateUrlSync) fails to validate IPv4-mapped IPv6 addresses, enabling an attacker-controlled n8nApiUrl to cause the server to make HTTP requests to internal networks, cloud metadata endpoints, or lo...

n8n-mcp's IPv4-mapped IPv6 addresses bypass SSRF protection in validateUrlSync(), enabling full SSRF for SDK embedders

Impact In the SDK embedder path N8NDocumentationMCPServer constructor, getN8nApiClient, and validateInstanceContext, the synchronous URL validator in SSRFProtection.validateUrlSync had no IPv6 checks. IPv4-mapped IPv6 addresses such as http://::ffff:169.254.169.254 bypassed the cloud-metadata,...